Battery pack latch mechanism

ABSTRACT

A rechargeable battery pack including a housing, a plurality of battery cells at least partially positioned within the housing, and a latch mechanism. The latch mechanism including a first linkage member, a second linkage member in operable communication with the first linkage member, and a locking pawl directly coupled to the second linkage member and movable with respect to the housing between a locked position and an unlocked position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication No. 62/309,118, filed Mar. 16, 2016, which is herebyincorporated by reference.

FIELD OF THE INVENTION

The invention relates to rechargeable battery packs, and morespecifically to latch mechanisms for use with rechargeable batterypacks.

BACKGROUND OF THE INVENTION

Rechargeable battery packs are necessary to provide electrical power toboth power tools and other forms of electrically powered portabledevices. As the power and capacity of these devices continues to grow,greater and greater power requirements must be met by the battery packsthemselves. As a result, the size of the battery packs have generallyincreased over time as larger and more numerous cells are added to thedesigns. In such instances, the ergonomics of the battery pack may needto be modified so as to allow the user to grasp the larger battery packhousing and still have access to the necessary controls.

SUMMARY OF THE INVENTION

In one embodiment, a rechargeable battery pack includes a housing, aplurality of battery cells at least partially positioned within thehousing, and a latch mechanism. The latch mechanism includes a firstlinkage member having a first end coupled to the housing, a second endopposite the first end and movable with respect to the housing, acontact surface accessible by the user from outside the housing, and afirst engagement point defined on a surface opposite the contactsurface. The latch mechanism also includes a second linkage memberhaving a first end coupled to the housing, a second end opposite thefirst end and movable with respect to the housing, and a secondengagement point positioned between the first end and the second end.Force is transmitted between the first linkage member and the secondlinkage member via the first engagement point and the second engagementpoint. The latch mechanism also includes a locking pawl coupled to thesecond end of the second linkage member, wherein the locking pawl ismovable with respect to the housing between a locked position and anunlocked position.

In another embodiment, a rechargeable battery pack for use with anelectrical device having a battery pack receptacle, the rechargeablebattery pack including a housing defining a center axis extendinglongitudinally therethrough, a plurality of battery cells at leastpartially positioned within the housing, and a latch mechanism. Thelatch mechanism includes a first linkage member movably coupled to thehousing, the first linkage member including a first engagement point.The latch mechanism also includes a second linkage member movablycoupled to the housing, the second linkage member including a secondengagement point in operable communication with the first engagementpoint, wherein force is transmitted between the first linkage member andthe second linkage member via the first engagement point and the secondengagement point. The latch mechanism includes a locking pawl coupled tothe second linkage member and movable with respect to the housingbetween a locked position, in which the locking pawl is a first distancefrom the center axis, and an unlocked position, in which the lockingpawl is a second distance from the center axis, which is less than thefirst distance.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a battery pack.

FIG. 2 is a section view of the battery pack take along line 2-2 in FIG.1.

FIG. 3 is a perspective view of an actuator of the battery pack.

FIG. 4 is a perspective view of a pawl member of the battery pack.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of embodiment and the arrangement of components set forth inthe following description or illustrated in the following drawings. Theinvention is capable of other embodiments and of being practiced or ofbeing carried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION

FIGS. 1-2 illustrate a rechargeable battery pack 10 including a latchmechanism 14 according to one embodiment of the invention. The batterypack 10 includes a housing 18 having battery cells 26 positionedtherein, and a pair of latch mechanisms 14 positioned on opposite sidesof the housing 18 and each being configured to releasably couple thebattery pack 10 to a power tool or other device (not shown). During use,at least a portion of the housing 18 is configured to be inserted into abattery pack receptacle (not shown) of a corresponding power tool orother electrical device to bring the electrical contacts 30 of thebattery pack 10 into electrical communication with the power tool.Furthermore, the latching mechanisms 14 are configured to releasablesecure the battery pack 10 within the receptacle during use.

The housing 18 of the battery pack 10 includes a base portion 19 and aconnecting or tower portion 22 extending from the base portion 19. Thebase portion 19 of the housing 18 is substantially rectangular in shapehaving a top wall 20, a bottom wall 21 opposite the top wall 20, a frontwall 23 extending between the top wall 20 and the bottom wall 21, and apair of sidewalls 24 spaced a distance from one another and extendingbetween the top wall 20 and the bottom wall 21. The housing 18 alsoincludes a center axis 63 extending longitudinally through the baseportion 19.

The tower portion 22 of the housing extends outwardly from the top wall20 of the base portion 19. The tower portion 22 also includes one ormore electrical contacts 30 (described above) configured to engageelectrical contacts (not shown) of the battery pack receptacle when thetower portion 22 is positioned therein.

Illustrated in FIGS. 1-2, each latch mechanism 14 of the rechargeablebattery pack 10 is substantially similar in layout and operation. Assuch, only one latch mechanism 14 will be described in detail herein.The latch mechanism 14 includes a first linkage member or button 34, asecond linkage member 38, and a locking pawl 42 coupled to the secondlinkage member 38 and configured to selectively engage a correspondinglocking aperture (not shown) of the battery pack receptacle. During use,the latch mechanism 14 is adjustable between a locked position, in whichthe tower portion 22 of the battery pack 10 cannot be removed from thereceptacle, and an unlocked position, in which the tower portion 22 isremovable from the receptacle.

In the illustrated embodiment of the latch mechanism 14, the button 34is not directly in contact with the locking pawl 42. Rather, the button34 is in operable communication with the pawl 42 through the secondlinkage member 38. As such, the latch mechanism 14 permits the button 34to be positioned away from the locking pawl 42 and in a moreergonomically advantageous position without having to modify the shapeof the housing 18. Such a configuration is particularly useful withlarger sized battery packs where a user's hands are not be able tocompletely grasp the housing 18, generally requiring the buttons 34 tobe placed away from the locking pawls 42 and proximate the bottom wall21 of the housing 18. Thereby, the button 34 is positioned where it ismore easily grasped by a user, while the locking pawl 42 remainsproximate the top wall 20 of the housing 18 and closer to thecorresponding locking aperture in the battery receptacle. The linkage ofthe latch mechanism 14 also provides a mechanical advantage to theuser's inputs such that one of the force or distance being applied tothe button 34 is magnified at the locking pawl 42.

Illustrated in FIGS. 1-3, the button 34 of the latch mechanism 14 ispivotably coupled to the housing 18 of the battery pack 10 andpositioned such that it may be easily accessed by the user. The button34 is generally positioned proximate the bottom 44 of the battery packhousing 18 (i.e., opposite the tower portion 22) such that when the usergrasps the battery pack 10, the buttons 34 of both latch mechanisms 14are easily accessible by the user's thumb and forefinger simultaneously.

The button 34 is substantially rectangular in shape having a first end35 and a second end 39 opposite the first end 35. The button 34 alsoincludes a contact surface 46 accessible from outside the housing 18 andpositioned proximate the second end 39. A user applies force against thecontact surface 46 (e.g., toward the center axis 63) to actuate thelatch mechanism 14 and move the latch mechanism 14 between the lockedposition, in which the contact surface 46 is a first distance from thecenter axis 63, and an unlocked position, in which the contact surface46 is a second distance from the center axis 63. The second distance issmaller than the first distance. The button 34 also includes a pair ofpivoting ears 50 positioned proximate the first end 35 that arepivotably supported by the housing 18. The ears 50 also define a firstaxis 54 about which the button 34 pivots with respect to the housing 18during use. In other embodiments, the button 34 may be linearly movablewith respect to the housing 18 between the locked position and theunlocked position.

The button 34 also includes a first engagement point or member 36positioned opposite the contact surface 46 and between the pivoting ears50. The first engagement member 36 engages the second linkage member 38and transmits force therebetween. In the illustrated embodiment, thefirst engagement member 36 includes a bar coupled to the button 34 (FIG.2); however in other embodiments the first engagement member 36 mayinclude a hinge, splines, pad, protrusion coupled to or integrallyformed with the button 34, or other members able to transmit forcebetween the button 34 and the second linkage member 38. Together, thecontact surface 46, pivoting ears 50, and engagement member 36 form aclass 2 lever.

Illustrated in FIG. 2, the second linkage member 38 is an elongatedpiece of resiliently deformable material having a first end 58 coupledto the housing 18, and a second end 62 opposite the first end 58 anddirectly coupled to the locking pawl 42. The second linkage member 38also includes a second engagement point or member 37 in operablecommunication with the first engagement member 36 of the button 34. Inthe illustrated embodiment, the second engagement member 37 is thelocation or surface area at which the first engagement member 36contacts the second linkage member 38. In further embodiments, thesecond engagement member 37 may include a bar, a ridge, protrusion, orthe like coupled to or integrally formed with the linkage.

During use, the first engagement member 36 of the button 34 contacts thesecond linkage member 38 at the second engagement member 37 (e.g.,between the first end 58 and the second end 62) causing the secondlinkage member 38 to move about a second axis 52 positioned proximateits first end 58 (e.g., elastically deforms about the first end 58). Inturn, the motion of the second linkage member 38 about the second axis52 causes the second end 62 to move between a locked position, in whichthe second end 62 is positioned a first distance from the center axis 63of the battery pack 10, and an unlocked position, in which the secondend 62 is positioned a second distance, which is less than the firstdistance, from the center axis 63 of the battery pack 10. In theillustrate embodiment, the second axis 52 is substantially parallel thefirst axis 54. Together, the first end 58, the second end 62, and thesecond engagement member 37 form a class 3 lever.

In the illustrated embodiment, the first end 58 of the second linkagemember 38 is fixedly coupled to the housing 18 within a slot 66 formedin the housing 18. During movement, the body of the second linkagemember 38 deforms in order to permit the second end 62 to move about thesecond axis 52 between the locked and unlocked positions. In otherembodiments, the first end 58 of the second linkage member 38 may bepivotably coupled to the housing 18 by a lug, hinge, or the like topermit the second end 62 to move without deforming the body of thesecond linkage member 38.

Illustrated in FIGS. 2 and 4, the locking pawl 42 of the latch mechanism14 is generally L-shaped and includes a tooth 72 sized and shaped toengage a corresponding aperture (not shown) formed in the battery packreceptacle of the power tool. Once assembled, the locking pawl 42 isdirectly coupled to the second end 62 of the second linkage member 38and movable therewith. Specifically, the locking pawl 42 moves withrespect to the housing 18 between a locked position, in which thelocking pawl 42 is positioned away from the center axis 63 of thehousing 18 (FIG. 1), and an unlocked position, in which the locking pawl42 is positioned closer to the center axis 63 of the housing 18 (notshown). That is, the locking pawl 42 is adjustable with respect to thehousing 18 between a locked position, in which the tooth 72 engages thecorresponding locking aperture of the battery pack receptacle when thetower portion 22 is inserted therein, and an unlocked position, in whichthe tooth 72 does not engage the corresponding locking aperture of thereceptacle when the tower portion 22 is inserted therein. In otherembodiments, the locking pawl 42 may include more than one tooth (notshown).

Illustrated in FIG. 2, the latch mechanism 14 also includes a biasingmember 76 coupled to the housing 18 and configured to bias the latchmechanism 14 toward the locked configuration. More specifically, thebiasing member 76 includes a length of resiliently deformable material(i.e., metal) having a first end 80 coupled to the housing 18, and asecond end 84 moveable with respect to the first end 80. When assembled,the second end 84 of the biasing member 76 generally engages the secondlinkage member 38, applying force away from the center of the housing 18and therefore biasing the second linkage member 38 toward the lockedposition.

While the illustrated embodiment includes two latch mechanisms 14, eachpositioned opposite one another on a respective sidewall 24 of thehousing 18, it is to be understood that fewer or more latch mechanisms14 may be included as necessary to releasably secure the rechargeablebattery pack 10 to the corresponding power tool or electrical device.

To couple the battery pack 10 to a corresponding power tool, the usergrasps the housing 18 proximate the bottom 44 and inserts the towerportion 22 into the battery pack receptacle. The user then continues toadvance the tower portion 22 into the battery pack receptacle, causingthe locking pawl 42 of both latch mechanisms 14 to automatically biasfrom the locked position, toward the unlocked position (i.e., inwardlytoward the center axis 63 of the housing 18) as an inner wall definingthe receptacle contacts a beveled surface 90 of the teeth 72.

The tower portion 22 continues to advance into the battery packreceptacle until the contacts 30 of the battery pack 10 are inelectrical communication with the power tool. Furthermore, the tooth 72of each locking pawl 42 becomes aligned with the locking aperture of thereceptacle, at which time the force of the biasing member 76 causes thelocking pawl 42 to automatically bias from the unlocked position towardthe locked position and into the locking aperture. Once the locking pawl42 is in the locked position, the battery pack 10 may not be removedfrom the receptacle.

To remove the battery pack 10 from the power tool, the user must firstgrasp the bottom 44 of the housing 18 such that the user's fingerscontact both buttons 34 of the two latch mechanisms 14. The user thenapplies force to both buttons 34, squeezing inwardly toward the centeraxis 63 and causing the buttons 34 to pivot about the first axis 54 fromthe locked positioned to the unlocked position (e.g., the distancebetween the two buttons 34 decreases).

As the buttons 34 pivot inwardly about the first axis 54, the firstengagement member 36 of the button 34 contacts the second engagementmember 37 of the second linkage member 38 causing the second end 62 ofthe second linkage member 38 to move from the locked position and towardthe unlocked position (i.e., inwardly toward the center axis 63 of thehousing 18). As the second end 62 moves toward the center of the housing18, the locking pawl 42, which is attached thereto, also moves from thelocked position to the unlocked position (i.e., inwardly toward thecenter of the housing 18). As such, the distance between the two lockingpawls 42 decreases.

As both locking pawls 42 move from the locked to the unlocked positions,the teeth 72 of both pawls 42 exit the respective locking apertures ofthe power tool thereby allowing the tower portion 22 to be removed fromthe battery pack receptacle.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of one or more independent aspects of the inventionas described.

1. A rechargeable battery pack comprising: a housing; a plurality ofbattery cells at least partially positioned within the housing; and alatch mechanism comprising: a first linkage member having a first endcoupled to the housing, a second end opposite the first end and movablewith respect to the housing, a contact surface accessible by the userfrom outside the housing, and a first engagement point defined on asurface opposite the contact surface, a second linkage member having afirst end coupled to the housing, a second end opposite the first endand movable with respect to the housing, and a second engagement pointpositioned between the first end and the second end, and wherein forceis transmitted between the first linkage member and the second linkagemember via the first engagement point and the second engagement point,and a locking pawl coupled to the second end of the second linkagemember, wherein the locking pawl is movable with respect to the housingbetween a locked position and an unlocked position.
 2. The rechargeablebattery pack of claim 1, wherein the housing defines a center axisextending longitudinally therethrough, and wherein the locking pawl ismovable between an unlocked position, in which the locking pawl ispositioned a first distance from the center axis of the housing, and alocked position, in which the locking pawl is positioned a seconddistance from the center axis of the housing, and further wherein thesecond distance is greater than the first distance.
 3. The rechargeablebattery pack of claim 1, wherein the first linkage member is a class 2lever.
 4. The rechargeable battery pack of claim 3, wherein the secondlinkage member is a class 3 lever.
 5. The rechargeable battery pack ofclaim 1, wherein the housing includes a top wall and a bottom wall, andwherein the contact surface of the first linkage member is positionedproximate the bottom wall.
 6. The rechargeable battery pack of claim 5,wherein the locking pawl is positioned proximate the top wall.
 7. Therechargeable battery pack of claim 5, wherein the first end of thesecond linkage member is positioned proximate the bottom wall.
 8. Therechargeable battery pack of claim 1, wherein the first engagement pointincludes a bar in operable communication with the second engagementpoint.
 9. The rechargeable battery pack of claim 1, wherein movement ofthe second end of the first linkage member relative to the housingcauses the second end of the second linkage member to move relative tothe housing.
 10. The rechargeable battery pack of claim 9, whereinmovement of the second end of the second linkage member relative to thehousing causes the locking pawl to move between the locked and unlockedpositions.
 11. The rechargeable battery pack of claim 1, furthercomprising a biasing member configured to bias the locking pawl towardthe locked position.
 12. A rechargeable battery pack for use with anelectrical device having a battery pack receptacle, the rechargeablebattery pack comprising: a housing defining a center axis extendinglongitudinally therethrough; a plurality of battery cells at leastpartially positioned within the housing; and a latch mechanismcomprising: a first linkage member movably coupled to the housing, thefirst linkage member including a first engagement point, a secondlinkage member movably coupled to the housing, the second linkage memberincluding a second engagement point in operable communication with thefirst engagement point, wherein force is transmitted between the firstlinkage member and the second linkage member via the first engagementpoint and the second engagement point, and a locking pawl coupled to thesecond linkage member and movable with respect to the housing between alocked position, in which the locking pawl is a first distance from thecenter axis, and an unlocked position, in which the battery pack is asecond distance from the center axis, wherein the second distance isless than the first distance.
 13. The rechargeable battery pack of claim12, wherein the first linkage member is movable with respect to thehousing about a first axis, and wherein the second linkage member ismovable with respect to the housing about a second axis, and wherein thefirst axis is parallel to the second axis.
 14. The rechargeable batterypack of claim 13, wherein the first axis and the second axis areparallel with the center axis.
 15. The rechargeable battery pack ofclaim 13, wherein the second axis is positioned proximate a first end ofthe second linkage member, and wherein the locking pawl is coupled tothe second linkage member opposite the first end.
 16. The rechargeablebattery pack of claim 12, wherein moving the second linkage member withrespect to the housing causes the first locking pawl to move from thelocked position to the unlocked position.
 17. The rechargeable batterypack of claim 12, wherein the first engagement point is a bar inoperable communication with the second engagement point.
 18. Therechargeable battery pack of claim 12, wherein the latch mechanism is afirst latch mechanism and the locking pawl is a first locking pawl, andfurther comprising a second latch mechanism including a second lockingpawl.
 19. The rechargeable battery pack of claim 18, wherein the firstand second pawls are movable with respect to the housing between alocked position, in which the first locking pawl is a first distancefrom the second locking pawl, and an unlocked position, in which thefirst locking pawl is a second distance from the second locking pawl,and further wherein the second distance is less than the first distance.20. The rechargeable battery pack of claim 12, further comprising abiasing member positioned within the housing and configured to bias thelocking pawl toward the locked position.